Quick action hydraulic jack



m 28,1936. w, G, STEPHENS 2,049,335

QUICK ACTION HYDRAULIC JACK Filed Sepn. 15, 1934 3 Sheets-Sheet 1 T? as V "(a @i Wyi; 1 v

I Inuentm I W. G .SZap/zehs Attorney July 28, 1936.- w. G. STEPHENS QUICK ACTION HYDRAULIC JACK Filed Sept. 15, 1934 3 Sheets-She'et 3 wii x niw PatentedJuly 2a, r93

UNITED STATES PATENT OFFICE I oincx ac'rroi r rfi muuc mcx Apphmlzeitel rtxirl z s lm z;4,203

' 3Clalms. ((31.60-42) This invention relates to a. hydraulic jack, the general object of the invention being to provide means whereby the movable part of the jack is quickly raised into engagement with the object to be lifted, after which the full force of the pressure of the fluid by the pump is utilized for lifting the object.

This invention also consists incertain other and arrangement of several parts, to be herein after fully described, illustrated in the accompanying drawings and specifically pointed out in the appended claims.

' In describing the invention in detail, reference will be had to the accompanying drawings wherein like characters denote like or corresponding parts throughout the several views, and in which: 7

Fig. 1 is an elevation of the improved Jack. Fig. 2 is a longitudinal sectional view thereof. Fig. 3 is a bottom plan view' of the valve body. Figure 4 is a longitudinal sectional view of the g5 mitting the fluid in the piston cylinder to return to the reservoir under pressure exerted by the high pressure'piston.

Figure 5 is an enlarged sectional view of the valve body.

so In these drawings, the numeral I indicates the base of the jack in which the lower end of the outer cylinder 2 is connected, this cylinder being closed by the cap 3 to which is threaded the upper end of the cylinder 4. A plug 5 is threaded in the as can 3 and closes the upper end of the inner cylinder 1. The .pump cylinder is shown at 6 and this cylinder 6 and the cylinder 4 are threaded in the sockets formed in the base I. The socket for the pump cylinder has an unthreaded chamber-form- 40 ing part in its lower end for receiving the valve body I which has its ends machined to tightly flt the bottom of the chamber and the lower end of the pump cylinder. Three passages 8, 3 and III are' formed in the valve bodyv and an annular 45 groove I2 is formed in the body intermediate the ends thereof anda port II connects a part of the groove with an intermediate part of the passage In, said passage having a valve seat above the port and a valve seat below the port. A pas- 50 sage I3 connectsthe lower'end of the chamber II, which formsa reservoir for the fluid used with the jack, with the groove I2, the chamber being formed by the space between the cylinders 2 and '4 and said e I3 has its upper end enlarged to for receiving a screen-carrying member I! through which the fluid is screened before entering the passage I3. I

The central passage 8 is controlled by an upwardly closing'valve I6 while a downwardly closing valve I'I engages the upper seat of the pas- 5 sage II and an upwardly closing valve I8 engages the lower seat of said passage.- An upwardly closing valve I3 rests upon a seat in the passage 9 by a spring 20. Any suitable means may be used for limiting the opening movement of the valves I6, 10 I1 and I8. A groove 2I in the bottom of the valve body I intersects the passages 9 and III as shown in Figures 3 and,5.

A tubular upright stem 22 has its lower end threaded-in a boss 23 in the bottom of the socket 15 in the base I which receives the inner cylinder 4 I and the upper end of this stem;22 is enlarged to provide a piston 24 and a passage 25 in the base' I has one end in communication with the bore of the stem 22 which extends through the top of the 20 piston 24 and the other end of the passage 25 is in communication with the lower end of the cenjack, showing the high pressure piston in raised;- position and the valve body in position for pertral passage 8 of the valve body. A second pas-. sage 26 in the base connects the lower end of the cylinder 4 with the passage 3 in the valve' body. 25

The lower end of the member 21 is enlarged to provide a piston part 30 which carries the cup washer 3| held in place by the ring 33 and the screws 34.

A pump plunger is shown at 35 and has its 35 7 upper end forked, betweenthe prongs of which is pivoted an intermediate part of a handle member 36, the inner end of which is connected by the links 31 with an upright 38 formed on an exterior part of the base. A packing gland 39 is 40 threaded to the upper end of the pump cylinder for forming a tight connection between the cylinder and the plunger and a collar 40 fits around the pump cylinder which is of hexagonal shape 7 as shown in Fig. 1. By placing a tubular handle,

in engagement with the handle I attached to the collar, the collar and pump cylinder can be turned to raise and lower the pump cylinder in its socket in the base I. Thus, by partly rotating the pump cylinder in one direction to cause it to move upwardly due to its threaded engagement with its socket. the valve body will have a certain amount of movement in its cham- 1 her so that the fluid in the cylinder 4 will pass into. the chamber and then return to the reservoir .55

l4 through the passage It. When the pump cylinder is screwed downwardly into engagement with the valve body, a fluid-tight connection is formed between the .valve body and the bottom of the 5 chamber which it occupies. I \The reservoir can be filled with fluid through the supply opening 43 which is closed by a plug 44 and a spiral pipe 45 is located in the upper part of the reservoir and has its upper end in communication with the top part of the cylinder 4 and its lower end in communication with the reservoir. This pipe permits fluid in the cylinder I to pass back into the reservoir when the movable part of the jack has been lifted to' its shape shown with its lower end slightly above the top level or the fluid in the reservoir l4, fluid will not pass from the reservoir into the cylinder 5 if the jack should be placed on its side, for instance, as it would if only a port connected the upper part of the reservoir with the upper part of the cylinder 4. This spiral pipe will act as a trap to prevent the fluid from passing from the reservoir into the cylinder 5 with the jack placed on its side or upset and the pipe acts as a breather for the reservoir and also acts to permit the fluid to flow from the cylinder 4 back into the reservoir when the piston is in raisedposition, as shown in Fi 4. I

From the foregoing, it will be seen that with the parts in their lowermost positions, when the pump plunger is raised, the suction created thereby will cause fluid to pass from the reservoir it through the passage l3 and groove 12 into the passage III, by the valve ll into the lower end of the pump cylinder. Then, when the plunger is depressed, this fluid will close the valve. ii and will be forced through the passage 8 past the valve 46 and through the passage 25 into the bore of the stem 22 and then'escapeinto the upper end of the chamber 28 above the piston 2d and this fluid will quickly raise the member 2'! against e the object to be lifted. The spring 20 will hold the valve is upon its seat. As the member 21, which may be called the high pressure piston moves upwardly, it will create a vacuum in the bottom of the cylinder 4 so that fluid will flow from the reservoir through the passage I3, groove I2 and downwardly through the passage it past go the valve I8, through the groove 2i and then through the passage 26 into the bottom of the cylinder 6. When the high pressurepiston 21 has-reached a position where the pressure in the lower part of the cylinder 6 overcomes the spring 20 of valve I9, then said valve opens so that the downward movement of the pump plunger will force fluid through both of the passages 25 and 26, the valve l8 remaining closed. Thus'the high pressure piston acts to lift the object. when 00 the flared part 29' ofthe chamber in the piston 21 reaches the piston 24, valve l9 closes and yalves l1 and 16 take care of the jacking action.

As will be seen, the low pressure pistons '22 and 24 act to raise the high pressure piston 27 to the object to be lifted very quickly and then the full force of the compressed fluid acts to raise the piston 21 to lift the object. As before stated,

' when the jack is to be lowered, it is simply necessary to partly. raise the pump cylinder 6 so that the fluid can escape from thejack cylinder 1 into the reservoir, past the valve body.

- -It is thought'from the foregoing description that the.advantages and novel features of the invention'will be readily apparent.

1g It is to be understood that'changes may be made highest position and by making the pipe of the are placed in communication in the construction and in the combination and arrangement of the several parts, provided that such changes fall within the scope of the appended claims. 5

I claim:

1. In a hydraulic jack, a base, a reservoir ca ried by the base, a cylinder carried by the base, a high pressure piston located in the cylinder and having a part passing through the top thereof, said piston having a cylinder therein, a stationary low pressure piston connected with the base and fitting in the cylinder of the high pressure piston and having a bore passing therethrough, a pump cylinder threaded in the base, a plunger operating therein, conduits connecting the pump cylinder with the bore and with the first mentioned cylinder, valve means in the lower part of the pump cylinder for first leading the. compressed fluid from the reservoir into -the bore of the low pressure piston to quickly raise the high pressure piston and then to cause the compressed fluid. to raise the high pressure piston, said valve means being held in downward position by threading the pump cylinder downwardly in the base and rising under the action of the compressed fluid with the pump cylinder partly unthreaded from the base, the conduit in the base connecting the passages withthereservoir when the valve means are in raised position.

2. A hydraulic jack of the class described comprising a base having a pair of sockets therein, a reservoir carried by the base, a cylinder threaded in one socket and passing through the reservoir, 9. pump cylinder threaded in the other socket, a valve body in the lower part of the pump socket and held against movement when the pump cylinder is turned downwardly in the'socket, a high pressure piston fitting in the first mentioned cylinder andhaving a part passing through the top thereof and provided with a cylinder in its lower end, a stationary low pressure piston fitting in the last mentioned cylinder and having a bore passing therethrough, the upper end of the low pressure piston being enlarged to snugly'fit the walls of the cylinder in the high pressure piston, said bwe having passages therein, one connecting the lower end of the socket of the pump cylinder to thefirst mentioned cylinder and the other connecting the pump cylinder socket to the bore of the lower pressure piston, said base havvoir with the lower end of the socket for the pump cylinder, said valve body having vertical passages therein, the first vertical passage having an intermediate part communicating with the passage leading from the reservoir, valves in said first passage, one located above the said intermediate partand the other below said part, the second vertical passage connecting the pump cylinder with the bore of the low pressure piston, an upwardly closing valve in the last mentioned vertical passage, the third vertical passage con-' necting the pump cylinder with the passage leading to the first mentioned cylinder, an upwardly closed spring pressed valve controlling said third vertical passage, the lower end of said valve body having a groove therein connecting the first vertical passage with the third passage, said valve body against the actionof the compressed fluid when the pumpcylinder is partly unthreaded from the socket in the base whereby the passages leading to the first cylinder and to the bore of the low pressure piston with the passage leading from the reservoir.

3. In a hydraulic jack, a reservoir, 9. cylinder passing through the reservoir, a plunger located in the cylinder and passing through the upper end of the same, pump means for forcing the fluid from the reservoir into the lower end of the cylinder to raise the plunger and a. spiral pipe in the reservoir and having its upper end WILLIAM G. STEPHENS. 

